<html>
<head>
    <meta name='viewport' content='width=device-width,initial-scale=1'>
</head>
<script>
      let uploaded = 0;
      let buf = new Uint8Array(1024 * 50);
      let start = Date.now();
      var rs = new ReadableStream({
         pull(ctrl) {
            uploaded += buf.byteLength;
            crypto.getRandomValues(buf);
            ctrl.enqueue(buf);
            if ((start + 1000) < Date.now()) { ctrl.close() };
         }
     });
      function test(url) {
            fetch(url, {
                  method: 'POST',
                  body: rs,
                  duplex: 'half'
            }).then(r => JSON.stringify( r.json()) ).then(console.log).catch();
            console.log('execute end');
      }
       function testError(url) {
            fetch(url, {
                method: 'POST',
                body: rs,
                duplex: 'half'
            }).then(r => JSON.stringify(r.json()) ).then(console.log);
       }
</script>
<body>
<div onclick='test()'>test post chunked http body.</div>
test()
</body>
</html>